1. Field of the Invention
The present invention relates to feeding controls for forage grinders.
2. Prior Art
The use of forage crop grinders comprising large tubs which rotate about a vertical axis and which move the forage across a rotating cylinder has expanded in recent years. The type of grinder has been known for many years, and is typically illustrated in U.S. Pat. No. 2,650,745 to W. H. Oberwertman, dated Sept. 1, 1953.
The grinding cylinders are generally fixed as to the area of the cylinder exposed to the forage crop, and any feed rate change is accomplished by varying the speed of rotation of the feeding tub. However, in many instances this variable speed is expensive to make, and does not permit controlling the feed rate with sufficient precision to keep the grinder operating at maximum efficiency in all types of forage crops.
Feed controls for different types of grinders or choppers also are known. For example, U.S. Pat. No. 2,696,330, in FIG. 5 shows an adjustable gate which is used for regulating the feeding of granular materials from a hopper into a type of rotating cylinder which is used for spreading material.
U.S. Pat. No. 1,688,770 issued to H. G. Woodhead on Oct. 23, 1928 shows a type of adjustable gate for a feed control on a cereal cutting machine. The gate is a type of slide that is manually adjusted to regulate the size of an opening from a hopper into the cylinder. The gate is used in combination with a hopper that has a rectangular discharge opening leading to the cylinder. In the tub grinder, there is no such hopper that has a discharge opening leading into a cylinder chamber, but as will be explained, the forage crop or hay is moved across the top of a rotating cylinder that protrudes into the hopper area.